There was an error published in Development 132, 4635-4644.

In Fig. 2, the incorrect image was shown in panel K. Owing to an error during figure assembly, Fig. 2K is a duplication of the wild-type embryo image shown in Fig. 5A. The corrected Fig. 2 appears below.

This error does not affect the conclusions of the paper. The authors apologise to readers for this mistake.